The invention concerns an ink cartridge holder for delivering ink to printing machine ink systems, with a cover which seals the ink cartridge holder shut and allows compressed air to build up inside the holder in order to squeeze ink out of a cartridge, with a locking mechanism for locking the cover in the closed position and for unlocking when the cover is opened, plus a valve to control the delivery and extraction of air in relation to the inside of the holder, said valve being operable depending on the locked or unlocked position of the cover.
For the purpose of delivering printing ink in instances requiring only small amounts of ink it is customary to employ cartridges out of which the ink is squeezed using suitable equipment. There are various prior art squeezing devices suitable for the stated purpose, consisting, for example, of a cartridge holder which can be sealed shut by a cover. After sealing the holder, compressed air is introduced to squeeze the ink out of the cartridge through the open base of the holder. The present invention concerns a holder of this type which functions as a device for squeezing out ink.
DE 196 32 717 C2 discloses a pneumatic cartridge squeezing device of the above kind. The cover can be fixed in place on the tube-shaped holder by means of a bayonet lock. Inside the cover there is an air inlet through which compressed air can be introduced into the top portion of the holder below the cover. The ensuing cushion of compressed air presses down on the cartridge piston, driving it downward so that the ink is squeezed down out of the cartridge. This publication concentrates in particular on means for sealing an annular gap which may occur between the cartridge and the holder if the cartridge does not fit snugly in the holder. In the absence of further details, it may be assumed that the cover is placed on the holder by hand and that the compressed air is delivered and extracted manually.
DE 296 02 801 U1 also concerns a device for squeezing cartridges. Here, too, the subject is a holder which can be sealed by means of a cover. The aim is to overcome sealing problems to permit squeezing of cartridges of different formats. The operations to close the cover and control the compressed air are apparently manual.
EP 716 923 B1 describes another squeezing device for cartridges comprising a cylindrical holder which can be sealed by means of a flap cover to which a compressed air line can be connected. The flap cover is apparently closed and opened by hand. The process of delivering and extracting the compressed air is also manual.
DE 198 54 494 C2 describes another cartridge holder with a cover for sealing the latter and a valve for delivering compressed air through the cover. This document focuses primarily on operating safety. Hence the idea is to ensure that compressed air can only be delivered when the cover is properly closed, and that the cushion of compressed air is properly reduced before the cover is opened. With this in mind a valve is provided to control the air, said valve being connected to the cover via a control device so that the valve can be operated when the cartridge holder is closed with the cover.
All the prior art cartridge squeezing devices require a greater or lesser degree of manual intervention in order to change the cartridge. This means the printing machine has to be constantly monitored by an operator. It is not possible, even for a limited period of time, to keep ready a stock of ink greater than the volume contained in a single cartridge.